1. Field of the Invention
The present invention relates to a driving circuit, system, and driving method for a gyro sensor, and more particularly, to a gyro sensor driving circuit for driving a vibration-type gyro sensor, a gyro sensor system including the same, and a gyro sensor driving method.
2. Description of the Related Art
Gyro sensors, which detect an angular velocity, are widely used for attitude control of aircrafts, rockets and robots, vibration compensation of cameras and telescopes, anti-slide and anti-rotation systems of vehicles, navigation systems, and so on. In recent times, gyro sensors are also mounted on smartphones to enhance applicability thereof.
Gyro sensors are classified into various types such as a rotary-type, a vibration-type, a fluid-type, an optical-type, and so on. The vibration-type gyro sensors are currently used for mobile products. The vibration-type gyro sensors may be generally classified into two types, a piezoelectric-type and a capacitance-type. Currently-used vibration-type gyro sensors are mostly applied to a capacitance-type comb structure, and partially applied to the piezoelectric-type.
The piezoelectric-type gyro sensor generally detects a magnitude of angular velocity by Coriolis' Force. Since a large signal magnitude can be obtained under the condition of vibration at a resonance frequency magnitude of mass, a driving circuit is very important.
A conventional driving method is a method of receiving a signal of a charge amplifier, in which a charge of a vibration-type sensor is converted into a voltage, to change a phase of the signal by 90° at a phase shifter, and amplifying the signal to apply a voltage to the vibration-type sensor again. Conventionally, the method is classified as a method of amplifying a signal at a final stage to apply the signal in a sine waveform, or a method of applying a signal in a pulse. Of course, while the signal is applied in a pulse, an output of the vibration-type sensor is represented in a sine waveform.
Conventionally, a sensor output is determined by combining a driving signal portion and a gyro signal component portion. However, when the driving signal portion is too large, the sensor may be malfunctioned or the signal may be saturated, a sensor signal cannot be appropriately detected. Accordingly, a driving signal level should be adjusted so that the signal is not saturated.